California’s groundwater reservoirs got a major boost during last year’s record wet season, offering a glimmer of hope for the depleted underground aquifer’s that remain in a long-term deficit. The 2023 water year, which was marked by above average rainfall and a concerted effort to recharge reservoirs, led to the addition of at least 4.1 million acre-feet of water underground, according to data released by the California Department of Water Resources. Much of that recharge took place in the San Joaquin Valley, where aquifers have been heavily taxed by pumping for agriculture. Glen and Colusa counties north of Sacramento saw major groundwater gains, as did Ventura and Santa Clara counties. This groundwater boost was driven in part by deliberate efforts to recharge the state’s vast underground reservoirs, which accounts for about 40% of California’s total water supply and is relied on more heavily during periods of drought. Most recharge is done by allowing water to pool on a piece of land, sometimes in specific recharge basins, and then slowly soak into the ground. Reduced groundwater pumping and enhanced conservation measures also played a role in stashing supplies underground.
This latest groundwater data comes from water agencies, which were required to file reports with the state last month, and captures the last “water year” from Oct. 1 to Sept. 30. The data is a product of the state’s Sustainable Groundwater Management Act, passed in 2014 as the state’s first effort to regulate groundwater. It requires local water agencies to manage their aquifers sustainable levels by 2040. Local and regional water agencies such as the Westlands Water District, one of the state’s largest irrigation agencies that serves Fresno and Kings counties, last year bolstered new programs that encourage groundwater recharge. Westlands spokesperson Elizabeth Jonasson said the agency recharged record amounts of water, nearly 162,000 acre-feet during the 2023 water year and around 200,000 acre-feet since then.
CALIFORNIA’S GROUNDWATER DEFICIT REMAINS
After decades of over-pumping to irrigate California’s agricultural heartland, the state’s groundwater reserves remain in a long-term deficit. In some parts, so much water has been pumped from the ground that wells have run dry and the land has sank. While no one knows the exact amount of water that can be stored within California’s 515 groundwater basins, DWR estimates the total storage capacity at somewhere between 850 million and 1.3 billion acre-feet. Between 2022 and 2023, according to the new data, the nearly 100 groundwater basins and sub-basins tracked by the state logged 8.7 million acre-feet of total additional water. During the previous three years, however, those basins experienced losses of almost twice that amount, the data show. Experts like Dr. Pablo Ortiz-Partida, water and climate researcher at the Union of Concerned Scientists, are celebrating the good news of increased recharged but keeping it in context within the bigger problem that will take many more years to solve. From Sacramento Bee